#market trends

I'm looking for some recommendations on economic models that can be used to predict market trends. I've been reading about the Gordon Growth Model and the Discounted Cash Flow model, but I'm not sure which one is more applicable to current market conditions. Can anyone with experience in this area provide some insight into which models they've found to be most effective? I'm particularly interested in hearing about any models that take into account external factors such as government policies and global events... do these models even exist??